fix(tracing-limit): group `info!(message = "foo")` and `info!("foo")` in same bucket

[WaterWhisperer]

Summary

Previously, these two equivalent log formats were treated as separate rate limit groups due to different callsite identifiers. Now, rate limiting is based on message content and contextual fields (like component_id) rather than callsite.

Vector configuration

N/A - This is an internal library change to the tracing-limit crate. No Vector configuration is required for testing.

How did you test this PR?

• Added a new test message_field_explicit_vs_implicit_same_bucket that verifies both info!(message = "Hello") and info!("Hello") are grouped under the same rate limit bucket
• All 9 existing tests in the tracing-limit crate pass
• Ran cargo test -p tracing-limit to verify no regressions
• Ran cargo clippy -p tracing-limit with no warnings

Change Type

• [x] Bug fix
• [ ] New feature
• [ ] Non-functional (chore, refactoring, docs)
• [ ] Performance

Is this a breaking change?

• [ ] Yes
• [x] No

Does this PR include user facing changes?

• [ ] Yes. Please add a changelog fragment based on our guidelines.
• [x] No. A maintainer will apply the no-changelog label to this PR.

References

• Closes: #24054

Notes

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[WaterWhisperer]

Hi @thomasqueirozb ,

I noticed that this PR needs some CI checks to be approved. .

Just wanted to check is there anything needs to be modified? I'm happy to rebase on the current main branch if needed

Thanks for your time and feedback!

[pront]

Hi @thomasqueirozb ,

I noticed that this PR needs some CI checks to be approved. .

Just wanted to check is there anything needs to be modified? I'm happy to rebase on the current main branch if needed

Thanks for your time and feedback!

Hi @WaterWhisperer, please resolve any merge conflicts. We recently made changes to this library.

[pront]

Also @WaterWhisperer, does this affect your pipelines in production? Trying to understand a bit better the motivation behind this solution.

[WaterWhisperer]

Also @WaterWhisperer, does this affect your pipelines in production? Trying to understand a bit better the motivation behind this solution.

@pront, thanks for asking!

To be honest, I'm not running this in a production environment yet. I'm a Rust enthusiast and a new contributor looking to improve my skills by solving issues in open-source projects. I found this issue interesting because the behavior of info!("msg") and info!(message="msg") being treated differently felt inconsistent.

I hope this fix helps make vector's internal logging more predictable!